Hard Drive problems, did it fail?

Yesterday, my sister was on the computer early in the morning (about 4:30am) and she woke me up, saying the computer wasn't working. So i try running Windows XP, in regular, safe mode, and with last known configuration.

She claimed there was a power surge, and now she can't get on. I know something wasn't working when windows XP took hours, for nothing to load. It always claimed something prevented the computer from starting properly. So I decided to format my hard drive, and reinstall it. It took forever to write anything to the hard drive (I checked to see if there was any problems with my CDRW/DVD ROM it's fine) and would then not write anything at all on the second phase of a clean install. Then I decided to change the partition to FAT32 and install Windows 98 as a 16bit subsystem so I can upgrade to Windows XP. It took a total of 4 Hours, and then rebooted upon completion.

I have installed windows 98 on this PC before, and took a total of 5 minutes. On reboot, a message saying there was an invalid disk, so I removed the windows 98 installation CD. Then I rebooted again. Same message.

I have reason to suspect that my hard drive has failed. She never turned the computer off properly, and we have had many power failures/brown outs recently. We unfortunately do not have a surge protector as of yet.

Are my suspicions true? Has my hard drive failed on me? If my Hard Drive indeed fail, what is the maximum size the A7V-VM motherboard can handle?